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The first cup of Italian coffee that some people drank was the fragrant and refreshing American style. Some were attracted by the exquisite coffee latte art, while others fell in love with the dense and smooth milk coffee... They are all inseparable from an ideally extracted espresso. A friend wanted to recreate the same delicious taste at home, so he asked Front Street how to adjust it. In this article, Front Street will talk about how to adjust the parameters of espresso extraction.
What is the best extraction?
No matter which method is used to brew coffee, the purpose is to release the positive flavor substances in the coffee through the water, thereby obtaining a delicious coffee liquid. 30% of the ingredients in coffee beans are soluble in water, such as fruit acids, caffeine, oils, carbohydrates, etc. Only about 20% of the aromatic small molecules with positive taste will be released first; the remaining macromolecules with woody and bitter taste will take longer to be extracted.
If you want to get a cup of delicious coffee, you must strive for positive coffee flavor and try to avoid the production of negative flavors. There are several widely recognized standards for the trade-off ratio. This is the Golden Cup Standard. Of course, when we extract a cup of Italian coffee at home every day, we rarely use professional equipment such as concentration testing. However, if we want to extract a cup of good coffee with moderate concentration and extraction rate, we must master several key factors that affect extraction.
What parameters do you need to know for espresso extraction?
There are many factors that affect the flavor of a coffee bean to a cup of coffee liquid, including grinding degree, coffee machine boiler pressure, water temperature, powder filling pressure, powder amount, extraction time, extraction liquid weight and other factors and details. Normally, the pressure and water temperature of the coffee machine are set and cannot be changed easily. The powder distribution and filling pressure will be controlled according to the barista's habits. The four major factors used to adjust extraction in daily life are powder volume, time, liquid weight, and grinding degree.
Grinding degree
The thickness and uniformity of the grind are the most important factors affecting the change in flow rate from cup to cup of espresso. With just a 1 gram difference in powder volume, the drain time required to extract the same amount of espresso liquid will differ by several seconds. When the size of the coffee powder particles is uneven, the resistance to water passing through the high-density areas after packing will be greater, and the extraction distribution will become inconsistent. The grinding method will directly affect the flow rate, time and flavor of the coffee liquid.
Powder to liquid ratio
The ratio of the amount of powder to the weight of the extraction liquid is what we often call the powder-to-liquid ratio, which is a relatively intuitive extraction parameter. The amount of powder depends on the capacity of the powder bowl model in the handle, which is divided into double portion and single portion. For example, the Front Street store coffee machine uses a double portion of 20 grams of coffee powder. Adjust it up or down based on this parameter (accurate to 0.1 grams). Since the ratio of powder to liquid is not fixed, the amount of coffee liquid output depends on the expression of coffee flavor.
In the past, baristas did not have accurate weights and would directly observe the color change of the oil to determine the amount of liquid. When the liquid first came out, it was dark brown and relatively rich. Over time, the color slowly turned to golden yellow, and then to light yellow. Generally, when the oil turns white, it means that the extraction needs to be completed. The current espresso extraction standards are more stringent, more stable data are summarized, and the powder-to-liquid ratio also tends to a fixed reference value of 1:2. For example, the Front Street store uses 20 grams of coffee powder and the extract weighs 40 grams.
Extraction time
The time will be affected by factors such as grinding, amount of powder, and whether the coffee powder is uniform. It also affects the flow rate and powder-to-liquid ratio. Generally, the extraction time of espresso is between 25 and 30 seconds. When the powder-to-liquid ratio is determined, the shorter the extraction time, the faster the flow rate, and the less dissolved coffee substances; the longer the extraction time, the slower the flow rate, and the more dissolved coffee substances. Under the same powder-to-liquid ratio, the extraction time can only be changed by adjusting the coffee grinding degree and powder volume.
In daily extraction, if we want to control the concentration and extraction rate within the ideal range, the variables we can adjust usually include grinding degree and powder-to-water ratio, which are judged based on the taste of the espresso. For example, under the same extraction ratio, the espresso has negative flavors such as burnt and bitter, but the concentration is moderate. This may be because the time is too long, resulting in the extraction of burnt and bitter flavors. The general solution is to adjust the grinding degree to be coarser. When the espresso tastes weak and has low concentration, it may be due to insufficient extraction. You can add more powder or adjust the grinding size.
The above parameters are constantly changing with the extraction state. We need to pay more attention to the adjustment direction brought by the extraction variables in order to better grasp the high-quality flavor of the coffee in the cup.
Recommended espresso beans
Since the functions of most home espresso machines are not as stable as those of commercial machines, and the cup output is also very small, this also tests our grasp of the parameters. Therefore, Front Street recommends choosing Italian-style blended coffee beans with higher stability. Italian-style blending combines coffee flavors from different production areas and uses medium-dark roasting, which allows us to have a higher error-tolerance rate in extraction. There are four Italian blended coffees on the Front Street Bean List for everyone to choose from, and they ensure that only freshly roasted coffee within 5 days is shipped to ensure that it is still in the best tasting stage when you receive it.
Classic and mellow type - Front Street commercial blended coffee beans
Robusta washed coffee beans + Colombian washed coffee beans + Brazilian semi-dried coffee
For people who want to open a coffee shop, Front Street introduces a dark roast formula to produce espresso with rich golden oil and nutty aroma. When you taste it, there will be a burnt coffee bitterness, but it will be accompanied by a more creamy and full taste. After swallowing, the bitterness will also dissipate, leaving a fragrant aroma on your lips and teeth.
Slightly acidic and mellow type - Front Street black cocoa blend (100% Arabica) coffee beans
Yunnan washed arabica coffee beans + Brazilian semi-sun-dried coffee beans
This is the cost-effective representative of the espresso coffee beans launched by Front Street. Yunnan arabica coffee has a soft acidity and the mellow aroma of Brazilian Cerato coffee. The espresso coffee has a taste of caramel, nuts, and soft plum sourness.
Balanced aroma - Front Street premium blend of 100% Arabica coffee beans
Colombian washed coffee beans + Brazilian semi-sun-dried coffee beans
Adding Colombian coffee to the nutty tone of classic Brazilian coffee, the espresso presents a dark chocolate flavor, caramel sweetness, and a full roasting aroma.
Delicate wine aroma - sunflower warm sunshine blended with coffee beans
The espresso made from Ethiopian sun-dried red cherry coffee beans + Honduran sherry barrel coffee beans has a very rich vanilla and cream flavor with a strong aroma of wine. The aftertaste of caramel after swallowing is unforgettable. Whether it's an Americano diluted with water or a latte with milk, it has a rich aroma and taste.
You can now buy the above coffee beans online at the Taobao store “FrontStreet Coffee” (前街咖啡). FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou, China, and its Guangzhou retail shop sells coffee beans only. The shop carries dozens of coffee beans from different origins around the world, including carefully selected single-origin beans for V60 pour-over and espresso. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers.
The FrontStreet 2013 Yunnan coffee beans sold in the store come from the Typica variety grown at FrontStreet Coffee’s own plantation in Yunnan. The name comes from the year the brand and the plantation were founded. You can buy these beans from China’s Yunnan origin at the Guangzhou shop and at FrontStreet’s Taobao store.
FrontStreet coffee beans are freshly roasted within 5 days and deliver consistently excellent quality and great value. Orders placed before 17:00 are shipped the same day, and most areas within Guangdong Province receive them the next day.
FrontStreet Coffee Taobao store: https://qianjiecoffee.taobao.com
Or search for “前街咖啡” (FrontStreet Coffee) on Taobao
Important Notice: FrontStreet Coffee has moved to a new address: 315, Donghua East Road, Guangzhou (coffee beans only)
Tel: 020 38364473
